2012 November 20

Holder for Ag/AgCl electrodes

Holder for wires, to be laser cut from acrylic. The red lines are cut lines, the black ones are just engraved. The black lines are 1cm apart, and are intended for immersing the wires to a consistent depth.

Prototype holder laser cut from acrylic, with two loops of wire in the intended positions. (Note: this is 24-gauge brass wire, not sliver wire, as I’ve not yet had time to buy fine-silver wire.)

Yesterday, I got a few minutes of assistance from a grad student from Gabriel Elkaim’s lab to cut the design out of a scrap of ¼” acrylic I had sitting around.

The picture to the left shows the new design, and the one to the right what the actual design looks like. A silver wire is wound around one ear, through the “armpit”, and back up to the same ear, where it is wound again. Alligator clips can be clamped on the wires at the ears, to make the transition from silver to copper wires.

The left and right wires are parallel, about 2cm apart, and can be dipped to a depth of 1cm, 2cm, or 3cm (immersing 2cm, 4cm, or 6cm of wire on each side). The feet and body are narrow enough to stand on the bottom of a standard 10 oz. clear plastic cup, and the alligator clips can be tilted to support the holder by resting against the top rim of the cup. We could probably even support the holder on the alligator clips, to adjust the depth.

I drew the design with Inkscape, but the laser cutter did not interpret the Inkscape SVG correctly, so I used the DXF output format from Inkscape to give to the laser cutter.
I’ll make a dozen of these for the lab, but for the final design I’ll make two modifications: I’ll engrave a face on holder (just for fun) and I’ll have the acrylic supported on blocks in the laser cutter, so that we don’t get the sloppy burn and melt marks on the back from the support grid.